Fabrication of Superhydrophobic Coating Using Stearic Acid Doped with Zinc Oxide on SS400 Steel Strips Substrate

This study presents a novel approach to identify the optimal parameter to develop a superhydrophobic coating on SS400 carbon steel substrates by stearic acid combined with zinc oxide coating. The surface modification involved chemical etching and chemical bath deposition using stearic acid with varying etching times, stearic acid concentrations, and stearic acid to zinc oxide mole ratios. The optimum value of surface modification on the contact angle and water sliding angle was investigated using Taguchi’s method combined with the assignment of weight to convert a multi-response problem into a single-response problem. The Fourier Transform Infrared (FTIR) spectroscopy result indicates the successful deposition of stearic acid on the substrate. The analysis of variance (ANOVA) result showed that the stearic acid to zinc oxide mole ratio significantly enchants the water contact angle. Optimum conditions were obtained from the multi-response performance index (MRPI) of the water contact angle and water sliding angle resulting in 60 min of etching time, 40 mM stearic acid concentration, and 0.08 stearic acid to zinc oxide mole ratio. The confirmation experiment that was conducted using optimum conditions resulted in a 155.6° water contact angle and 34.5° water sliding angle which is considered reproducible based on the evaluation conducted using the confidence interval that overlaps between the predicted and the confirmation experiment.